Flux-coated electrode



Feb. 25, 1936. JUDY 2,032,322

FLUX COATED ELECTRODE Filed April 10, 1934 lzmenz' (e,

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PRU L Patented Feb. 25, 1936 UNITED STATES FLUX-COATED ELECTRODE Paul R.Judy, Muncie, Ind., assignor .to Indiana Steel & Wire Company, Muncie,Ind., a corporation of Indiana Application April 10,1934, Serial No."#9346 2 Claims. (01. 219-s) It is the object of my invention to,produce a flux-coated electrode or weld-rod in which the flux-coatingnot only facilitates the welding operation and protects the weldingduring its mak- 5 ing and'forms only an easily removable slag, but alsoone in which such flux coating is made of readily obtainable andinexpensive materials.

In arc welding, as is well known, it is desirable to protect the moltenmetal both while it is being transferred from the electrode to the workand while the deposited metal is solidifying and C001? ing; and toprovide in the coating the necessary ingredients to accomplish thispurpose To protect during the solidifying and cooling, it is desirableto provide on the molten metal a thin.

film of protective material, and to have this film substantiallycontinuous and unbroken until the metal has solidified and'cooled; butto have the film of such character that when the whole is cold such filmis quite friable and easily removable. By maintaining the film unbrokenwhile the weld-metal is liquid, unevenness of the surface and of theboundary of the weld is in large measure avoided. While the samematerials 5 which protect the deposited metal also serve to some extentto protect the metal as it is being deposited from the electrode, thislatter protection may be more effectively obtained by providing anon-oxidizing gaseous envelope for the metal as it is being deposited;and this gaseous envelope can be obtained by providing in' the weld-rodcoating an organic material, such as 45 tain an unbroken protective filmwhile the de-.

posited metal is liquid anduntil it has solidified and cooled. Althougheither the ilmenite alone or (usually) the aluminum-bearing silicatealone is not friable, and tends in general to yield a slag 50 which ishard to remove, even withsodium silicate present, the co-presence of theilmenite and the aluminum-bearing alkali-metal or alkalineearthsilicate, such as feldspar or mica, makes a resultant 'slag which isquite friable and easily '55 removable.

In addition to these three fundamental ingredients, I may and desirablydo provide other ingredie'nts in the coating. The chief among these isan organic material, such as wood ur.

I Others may be ferro-manganese and gum afrabic; 5

but they are relatively secondary.

The accompanying drawing shows a coated welding electrode or weld-rodembodying my' invention: Fig. 1 is an elevation of such a coated weldingelectrode, partly broken away to show 10 a longitudinal section; andFig. 2 is a cross-section of such coated welding electrode, on the line2-2 of Fig. 1.

In such drawing, the metallic wire or rod Ill, usually a ferrous wire orrod of desired composi- 15 tion, is covered for all or the greater partof its length by a coating II; and this coating is made of the mixtureof ilmenite and an aluminumbearing alkali-metal or alkaline-earthsilicate,

with a binder silicate (such as sodium silicate), 20 desirably with woodflour, ferro-manganese, and gum arabic also present, asdescribed above.

The ilmenite, which is an iron titanate is suitably reduced to a powder,for intimate mixing with the other ingredients used. a 25 Thealuminum-bearing silicate is also reduced to'a powder, as by grinding,for intimate mixture with the other ingredients. It is most convenientlyeither feldspar or mica; but other aluminum-bearing alkali-metal oralkaline-earth silicates may be used, such as feldspathoids, zeolites,or epidotes. Various feldspars may be used, such as orthoclase, 'albite,oligoclase and labradorite; and various micas, such as biotite,muscovite, lepidolite, margarite, phlogopite, etc.

The binder silicate is desirably either sodium silicate or potassiumsilicate; desirably in' the form of water glass if sodium silicate isused, or of the analogous substance if potassium silicate is used.

These three ingredients may vary widely in their relative proportions.The ilmenite and the aluminum-bearing silicate may each vary from 10% toof the whole formed by these three desirably added in the coating. Ithas a multiple has several functions. Among these are that it helps inthe binding action, and also helps in furnishing the carbonaceous gases.It usually is present in relatively small amount, such as 2% to 15% ofthe total weight of ilmenite and the silicates.

I give below an example of a coating mixture which I have found veryeffective, and which embodies all of the ingredients discussed above,although not all of them are necessary:

Percent Ilmenite 10 to 40 Aluminum-bearing alkali-metal oralkaline-earth silicate (such as feldspar or mica) 10 to 40 Sodiumsilicate (dry basis) 20 to 60 Wood flour 10 to Farm-manganese 5 to 15Gum arabic 1120 5 In making the coating mixture, the ingredients aresuitably mixed in the desired proportions, and applied to the electrodecore in any suitable manner, as by being extruded thereon. The rod whichhas thus been coated is. suitably dried,

and is used in the usual manner of welding elecf trodes. It can beeffectively used in all positions,

not only in the so-called down-handwelding, in which the work is belowthe electrode, but also for welding on vertical surfaces and in overheadwelding. Also, the electrode is found not only to work with reversepolarity, or when it is connected to the positive side of the circuit,but also to work quite .well on fstraight polarity", or when it isconnected to the negative side of the circuit-a versatility of operationwhich is unusual.

I claim as my invention:---

1. A weld-rod having a coating containing 11- menite, mica, and a bindersilicate, with each of the first two forming from 10% to 40% of thetotal of the three.

2. A weld-rod having a coating containing 11- menite, mica, and a bindersilicate, with each of the first two forming substantially one-fourth ofthe total of the three.

PAUL R. JUDY.

